A connector structure for a window regulator mechanism using a wire of this kind is disclosed in Japanese Utility Model Laid-open No. 103376/1980. This conventional structure is shown in FIG. 3, where a wire 13 is inserted into a hole 21 formed in a hook 24. Then, the side surface of the hook 24 is firmly fixed to the wire 13. Subsequently, the hook 24 is fitted into a hole formed in a holder (not shown) for holding a windowpane to couple the wire 13 to the windowpane. The hook 24 retained in the hole in the holder drives the holder on its both end surfaces.
However, this conventional structure presents a problem as described below. Referring to FIG. 4, the end surfaces of the hook 24 are deformed, because they have been crimped. Accordingly, they are not planar. Thus, the pressure of contact applied between the hook 24 and the hole in the holder is quite large at some locations, deforming the hole in the holder. This gives a play between the holder and the hook 24. As a result, the holder becomes loose, and the windowpane rattles when a vehicle carrying the windowpane is running.